This invention relates to the method of an apparatus for establishing spatial coherency in electromagnetic energy transmitting systems; and particularly to such method and apparatus which use discrete iterative phase corrections across the transmitting aperture to establish far field phase coincidence across the transmitted beam.
In energy transmission systems such as laser transmitting arrangements, for example, atmospheric inhomogeneities and/or phase unbalances in the aperture feed system cause undesirable spreading of the transmitted beam. My U.S. Pat. No. 3,731,103 discloses basic techniques for establishing phase coincidence in such energy transmission systems. For example, in accordance with the just cited patent, optical arrays are separated into N effective subapertures with continuous phase control being effected on the radiation from each subaperture such that the energy propagated along all channels is in phase at a common remote location.
The subject invention extends the developments in this area of technology and has the advantage of being more readily adaptable to digital implementations than the prior art continuous (all channels being controlled simultaneously) "tagging" and control approaches.